The meconium microbiota shares more features with the amniotic fluid microbiota than the maternal fecal and vaginal microbiota

ABSTRACT

The early-life gut microbiota is associated with potential development of diseases in adulthood. The sterile womb paradigm has been challenged by recent reports that revealed the presence of the meconium, amniotic fluid, and placenta microbiome. This study aimed to explore the maternal origin of the microbiota of neonate meconium by using the PacBio single-molecule real-time circular consensus sequencing technology. Such technology could produce high fidelity reads of full-length 16S rRNA genes, improving the sensitivity and specificity of taxonomic profiling. It also reduced the risk of false positives. This study analyzed the full-length 16S rRNA-based microbiota of maternal samples (amniotic fluid, feces, vaginal fluid, saliva) and first-pass meconium of 39 maternal-neonate pairs. Alpha- and beta-diversity analyses revealed sample type-specific microbiota features. Most sample types were dominated by sequences representing different genera (Lactobacillus and Curvibacter in the amniotic fluid and vaginal fluid microbiota; Bacillus and Escherichia/Shigella in the meconium microbiota; Bacteroides and Faecalibacterium in the maternal fecal microbiota; Streptococcus and Prevotella in the maternal saliva microbiota). Moreover, specific operational taxonomic units (OTUs) were identified in all sample types. Dyad analysis revealed common OTUs between the meconium microbiota and microbiota of multiple maternal samples. The meconium microbiota shared more features with the amniotic fluid microbiota than the maternal fecal and vaginal microbiota. Our results strongly suggested that the meconium microbiota was seeded from multiple maternal body sites, and the amniotic fluid microbiota contributed most to the seeding of the meconium microbiota among the investigated maternal body sites.     

Transcervical minimally invasive esophagectomy: hemodynamic study on an animal model

BackgroundTranscervical esophagectomy is a less invasive procedure performed within mediastinum. However, the mediastinum offers limited surgical space and the surgery via this route differs from conventional minimally invasive esophagectomy. Therefore, the physiological study of this surgical approach on an animal model would be necessary before the procedure gained more popularity.MethodsWe conducted transcervical minimally invasive esophagectomy on animal model (swine) under CO₂ pneumomediastinum. The hemodynamic parameters were monitored using float catheter cannulated via right jugular vein. At different anatomical level (the upper, middle, and lower thoracic part of the animal esophagus), increased artificial pneumomediastinal pressures (0, 4, 8, 12, and 16 mmHg) were consecutively allocated to record the intra-operative changes of blood pressure, cardiac output (CO), central venous pressure (CVP), pulmonary artery pressure (PAP) and extravascular lung water (EVLW). Meanwhile, the surgical field under different pneumomediastinum pressure was recorded and balanced with animals’ hemodynamic changes to determine the optimal pressure for transcervical minimally invasive esophagectomy.ResultsThe animal procedures were accomplished without conversions. During the upper thoracic stage, increased CO₂ pressures did not lead to significant changes in hemodynamic parameters including the blood pressure, CO, CVP, PAP or the level of EVLW. During the middle thoracic stage, pneumomediastinum under 4–12 mmHg did not lead to significant changes in hemodynamic parameters. However, pneumomediastinum at 16 mmHg resulted in lower CO (P=0.038) when compared to 0–12 mmHg. During lower thoracic stage, as the pneumomediastinum pressures increased from 0 to 16 mmHg, significant decrease in CO (P=0.022), and increase in CVP (P=0.036) was recorded. In compared to 4 mmHg pneumomediastinum, the surgical field under 8–16 mmHg artificial CO₂ pneumomediastinum was suitable for mediastinal manipulation.ConclusionsDuring transcervical minimally invasive esophagectomy on animal model, the mobilization of swine thoracic esophagus with optimal pneumomediastinum pressure 8–12 mmHg is safe and effective based on hemodynamic analysis.     

Characterization of the biological properties and complete genome sequence analysis of a cattle-derived rabies virus isolate from the Guangxi province of southern China

In this study, a street rabies virus isolate, GXHXN, was obtained from the brain of one rabid cattle in Guangxi province of southern China. To characterize the biological properties of GXHXN, we first evaluated its pathogenicity using 4-week-old adult mice. GXHXN was highly pathogenic with a short incubation period and course of disease. Its LD₅₀ of 10^?6.86/mL is significantly higher than the LD₅₀ of 10^?5.19/mL of GXN119, a dog-derived rabies virus isolate. It also displayed a higher neurotropism index than the rRC-HL strain. However, the relative neurotropism index of GXHXN was slightly lower than that of GXN119. Analyzing antigenicity using anti-N and anti-G monoclonal antibodies (MAbs), all tested anti-N MAbs reacted similarly to GXHXN, CVS, and rRC-HL, but the reaction of anti-N MAbs to GXHXN was slightly different from GXN119. Moreover, 2/11 tested anti-G mAbs showed weaker reactivity to GXHXN than rRC-HL, whereas 4/11 showed stronger reactivity to GXHXN than CVS and GXN119, indicating that the structures of G might differ. In order to understand its genetic variation and evolution, the complete GXHXN genome sequence was determined and compared with the known 12 isolates from other mammals. A total of 42 nucleotide substitutions were found in the full-length genome, including 15 non-synonymous mutations. The G gene accounts for the highest nucleotide substitution rate of 0.70 % in ORF and an amino acid substitution rate of 0.95 %. Phylogenetic trees based on the complete genome sequence as well as the N and G gene sequences from 37 known rabies isolates from various mammals demonstrated that the GXHXN is closely related to the BJ2011E isolate from a horse in Beijing, the WH11 isolate from a donkey in Hubei, and isolates from dogs in the Fujian and Zhejiang provinces. These findings will be helpful in exploring the molecular mechanisms underlying interspecies transmission and the genetic variation of the rabies virus in different mammal species.     

人胰腺癌PANC-1细胞裸鼠移植瘤模型建立及其用于观察载siRNA纳米微粒体内效应的研究

 目的：探讨建立人胰腺癌PANC-1裸鼠移植瘤模型的最佳实验方法,并应用该模型进行载基因纳米微粒体内效应的研究。方法：将不同数量PANC-1细胞悬液接种于BALB/c (nu/nu)小鼠右侧背部皮下,当肿瘤体积达100 mm3时尾静脉注射siRNACY5.5纳米复合物进行活体荧光成像。此外,于尾静脉注射负载siRNAKras纳米复合物,蛋白印迹及免疫组织化学染色法观察肿瘤组织Kras蛋白表达水平。结果：1×107 cells/300 μL 接种成瘤率达100%,成瘤时间＜2周。荧光呈像及组织学检查显示载siRNA纳米微粒可靶向聚集在肿瘤组织发挥体内基因沉默效应。结论:本研究报道的人胰腺癌裸鼠移植瘤模型建立方法成瘤率达100%,成瘤时间短,是研究药物示踪和观察疗效的理想模型。     

Innate immune receptor NOD2 promotes vascular inflammation and formation of lipid‐rich necrotic cores in hypercholesterolemic mice

Atherosclerosis is an inflammatory disease associated with the activation of innate immune TLRs and nucleotide‐binding oligomerization domain‐containing protein (NOD)‐like receptor pathways. However, the function of most innate immune receptors in atherosclerosis remains unclear. Here, we show that NOD2 is a crucial innate immune receptor influencing vascular inflammation and atherosclerosis severity. 10‐week stimulation with muramyl dipeptide (MDP), the NOD2 cognate ligand, aggravated atherosclerosis, as indicated by the augmented lesion burden, increased vascular inflammation and enlarged lipid‐rich necrotic cores in Ldlr^?/? mice. Myeloid‐specific ablation of NOD2, but not its downstream kinase, receptor‐interacting serine/threonine‐protein kinase 2, restrained the expansion of the lipid‐rich necrotic core in Ldlr^?/? chimeric mice. In vitro stimulation of macrophages with MDP enhanced the uptake of oxidized low‐density lipoprotein and impaired cholesterol efflux in concordance with upregulation of scavenger receptor A1/2 and downregulation of ATP‐binding cassette transporter A1. Ex vivo stimulation of human carotid plaques with MDP led to increased activation of inflammatory signaling pathways p38 MAPK and NF‐κB‐mediated release of proinflammatory cytokines. Altogether, this study suggests that NOD2 contributes to the expansion of the lipid‐rich necrotic core and promotes vascular inflammation in atherosclerosis.     

Bone morphogenetic protein 4 inhibits liposaccharide‐induced inflammation in the airway

Bone morphogenetic protein 4 (BMP4) is a multifunctional growth factor that belongs to the TGF‐β superfamily. The role of BMP4 in lung diseases is not fully understood. Here, we demonstrate that BMP4 was upregulated in lungs undergoing lipopolysaccharide (LPS)‐induced inflammation, and in airway epithelial cells treated with LPS or TNF‐α. BMP4 mutant (BMP4^+/?) mice presented with more severe lung inflammation in response to LPS or Pseudomonas aeruginosa, and lower bacterial load compared with that in BMP4^+/+ mice. Knockdown of BMP4 by siRNA increased LPS and TNF‐α‐induced IL‐8 expression in 16HBE human airway epithelial cells and in primary human bronchial epithelial cells. Similarly, peritoneal macrophages from BMP4^+/? mice produced greater levels of TNF‐α and keratinocyte chemoattractant (KC) upon LPS treatment compared with cells from BMP4^+/+ mice. Administration of exogenous BMP4 attenuated the upregulation of TNF‐α, IL‐8, or KC induced by LPS and/or TNF‐α in airway epithelial cells, and peritoneal macrophages. Finally, partial deficiency of BMP4 in BMP4^+/? mice protected the animals from restrictive lung function reduction upon chronic LPS exposure. These results indicate that BMP4 plays an important anti‐inflammatory role, controlling the strength and facilitating the resolution of acute lung inflammation; yet, BMP4 also contributes to lung function impairment during chronic lung inflammation.     

Evidence for implicit self-positivity bias: an event-related brain potential study

We investigated the processing of self-related information under the prime paradigm using event-related potentials (ERPs) to provide evidence for implicit self-positivity bias in Chinese individuals. Reaction times and ERPs were recorded when participants made positive/negative emotional judgments to personality-trait adjectives about themselves or others. Faster responses occurred to self-related positive adjectives and other-related negative adjectives, indicating implicit self-positivity bias at the behavioral level. ERPs showed an interaction between prime and emotion at the P300 amplitude, with larger P300 amplitudes for words within the self-positivity bias, indicating that self-related information occupied more attentional resources. Larger N400 amplitudes elicited by words that were inconsistent with the self-positivity bias, suggesting that accessing non-self-relevant information is more difficult than self-relevant information. Thus, P300 and N400 could be used as neuro-indexes of the implicit self-positivity bias.     

Immunogenicity of recombinant human bocavirus‐1,2 VP2 gene virus‐like particles in mice

Human bocavirus (HBoV), a recently identified pathogen with a worldwide distribution is closely related to paediatric acute respiratory infection and gastroenteritis. The present study was performed to evaluate the immunogenicity of HBoV1 and HBoV2 virus‐like particles (VLPs) as vaccine candidates in mice. Both HBoV1 and HBoV2 VLPs were expressed in the bacmid virus–SF9 cell system. Mice were inoculated three times at 3‐week intervals with HBoV VLPs at one dose intramuscular (i.m.) or intradermal (i.d.) with or without the addition of the alum adjuvant. ELISA was used to detected antibody, and ELISPOT was used to test cellular immune responses. HBoV‐specific IgG antibodies were induced and alum adjuvant improved the antibody titres and avidity, while the inoculation pathway had no influence. T helper type 1/ type 2 immune responses were balanced induced by HBoV1 VLPs but not HBoV2 VLPs. Serum IgG antibody cross‐reactivity rates of the two subtypes were similar, but cross‐reactions of HBoV1 immunization groups were higher. The single i.m. group had more interferon‐γ‐secreting splenocytes. These data indicate that HBoV VP2 VLPs have good immunogenicity with induction of strong humoral and cellular immune responses, and they may be potential candidate vaccines for HBoV infection.